The largest online repair guide library for every car

About us
Contact support
FAQ
Sign up
Sign in

2018 Elantra Rough Idle and P0302 Code

0

Nicole W. · rep 0 · May 25, 1:59 AM · 1 replies · solved · Question

My 2018 Hyundai Elantra SE with about 75,000 miles has been running really rough lately, especially at idle. The check engine light came on, and I scanned it with my OBD-II tool. It's showing a P0302 code, indicating a misfire on cylinder 2.

I've already tried swapping the spark plug and coil pack from cylinder 2 to cylinder 1 to see if the code moves, but it stayed on cylinder 2. The car feels sluggish and sometimes stutters when accelerating from a stop.

What else should I be looking at? Could it be an injector issue or something more serious? Any advice would be appreciated!

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 25, 1:59 AM

0

ClearTheCode guidance (Hyundai · Diagnostics & codes)

Summary: For 2018 Elantra Rough Idle and P0302 Code, work through these steps on your 2015+ vehicle:

  1. Confirm the symptom — note when it happens (cold start, highway, after fuel fill, etc.).
  2. Scan codes — save all pending/stored DTCs; don't clear until you've recorded them.
  3. Check TSBs & recalls — look up your VIN for open campaigns and known fixes.
  4. Inspect the obvious — related fuses, connectors, fluid level, and recent repairs.
  5. Test the common fix — follow model-specific service procedures; one change at a time.
  6. Escalate if needed — burning smell, no brakes, overheating, or stalling in traffic → shop visit.

Owner reported: My 2018 Hyundai Elantra SE with about 75,000 miles has been running really rough lately, especially at idle. The check engine light came on, and I scanned it with my OBD-II tool. It's showing a P0302 code, indicating a misfire on cylinder 2.

I've already tried swapping the spark plug and coil pack from cylinder 2 to cylinder 1 to see if the code moves, but it stayed on cylinder 2. The car feels s…

This is educational guidance, not a substitute for hands-on diagnosis.

Menu

Help & account